Looks like my other message didn't go through. Agree re the slight rotational issues; and it being at about the level of a new-intermediate contributor from the samples around Adelaide I managed to look at.
I found sometimes, it would mistake bright concrete as part of a building footprint. Because of the simple way I split the files up, I've only got sporadic coverage - a few buildings per street from my 10% sample. I'm not sure if the original file is sorted by longitude/latitude in any way; or if the model simply missed many of these. @Andrew Harvey <[email protected]> - can you shed some light on this? On Wed, Oct 21, 2020 at 12:30 PM Andrew Harvey <[email protected]> wrote: > Also buildings which are touching like a shop fronts are just one polygon, > but I don't think you'd ever be able to do this too reliably without a > survey anyway. Even if there is a small gap between buildings eg a garage > and residence sometimes it will join them into a single polygon. > > What I feel it does do well is actually identify buildings, I haven't > found any false positives, only a few false negatives where a building is > hidden under dense tree coverage. > > On Wed, 21 Oct 2020 at 12:52, Andrew Harvey <[email protected]> > wrote: > >> On Tue, 20 Oct 2020 at 21:20, Simon Poole <[email protected]> wrote: >> >>> Just as a comment: there is nothing so time consuming as fixing badly >>> mapped buildings (essentially drawing them from scratch is nearly always >>> faster), I would only import building outlines that are at a quality level >>> that you would not want to change them except if the building itself has >>> been modified. >>> >> >> I took a look at these building footprints from Microsoft in Sydney, >> where we have high resolution aerial imagery with usually pretty good >> positional accuracy and orthorectification. >> >> The MS buildings aren't as good as hand tracing would be, but better than >> some of the worst mapping done through the HOT tasking manager building >> tracing projects. >> >> Compared to the DCS aerial imagery the alignment (rotation) is usually a >> fair bit off, but "good enough" basic footprints, the shape is just okay, >> not great, not terrible. >> > _______________________________________________ > Talk-au mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/talk-au >
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